Flexible plastic bags have come to be widely used to distribute and dispense liquids such as wine and syrups for preparing drinks. Such bags typically have a thin, flexible plastic wall having a dispensing spout or fitment sealed to the wall of the bag. In use, the flexible bag is filled with a flowable material to be dispensed, and the bag is packed in a relatively rigid container, e.g., a corrugated cardboard box, for distribution. At the point of use, the spout is extended through a hole in the side of the rigid container and a dispensing tap or service line connector is fitted thereto to control and direct the dispensing of the contents of the bag. Because the walls of the bag are thin and very flexible, the bag collapses as the contents are removed. As the liquid contents of the bag are dispensed, it is possible that one of the flexible bag walls may be drawn close to the spout, even when a substantial proportion of the contents remain in the bag, and may come to cover the inner end of the spout, thus blocking it and shutting off flow. Because of the pressure of the remaining liquid in the bag on the wall, it is difficult and troublesome to dislodge the wall from the spout and remove the blockage.
Accordingly, it has become customary to provide an evacuation channel or form within the flexible bag to prevent the thin wall from blocking the spout as the bag is emptied. One such example of an evacuation channel is disclosed in U.S. Pat. No. 4,138,036, to Curtis J. Bond (the “Bond patent”), the entire disclosure of which is incorporated herein by reference. The Bond patent discloses a helical channel or tube that is mounted in the spout and extends into the interior of the flexible bag. As described therein, the bag collapses around the evacuation channel. Accordingly, the wall of the bag cannot block the spout. Furthermore the evacuation channel provides a path for the contents to reach the spout even when the walls of the bag have collapsed around it, thereby assuring substantially complete drainage of the contents of the bag.
However, although the helical evacuation channel disclosed in the Bond patent is very effective, it is not well adapted to the more modern practice of forming flexible bags from a pair of walls made from a flexible plastic film and sealed together around their edges. Such bags are convenient because they are relatively flat in the unfilled condition, and, accordingly, are convenient to store and to ship to a location where they are to be filled. Because of the way in which the evacuation channel of the Bond patent is mounted, it extends some distance into the bag from the inner end of the spout. This prevents the bag from assuming the desirable flattened configuration. Furthermore, because of the mounting of the helical channel of the Bond patent, it is inserted into the bag after it is formed, which necessitates an extra manufacturing step.
Furthermore, the mounting of the helical channel disclosed in the Bond patent is not well adapted to use with collapsible bags for use with service line connectors that are provided with quick-disconnect fittings and valves. Such quick-disconnect fittings and valves may use a valve element that slides within the fitment or spout, projecting into the bag when actuated by the insertion of a service line connector and being withdrawn within the fitment to cut off the flow of contents when the connector is withdrawn. Because of possible interference between the slider of such a valve and an evacuation channel attached to the spout it has not been possible to mount an evacuation channel, and particularly a desirable helical evacuation channel, to the periphery of the spout as with the mounting arrangement of the Bond patent.
The evacuation problem becomes even more complicated when the fluids to be evacuated constitute viscous materials such as pastes, puree, sauces, slurries, cheeses, oil-based products, etc. Even with an evacuation channel described in the Bond patent, which helps to keep the spout open from one of the bag walls collapsing and shutting, a substantial amount of the fluid may remain in the bag, unevacuated, if the fluid is viscous and not easily flowable. Particularly, when a collapsible bag being evacuated is placed in a tray with its spout connected to fitment for dispensation purposes, the tray may be placed at an angle to help the flow of the fluid being evacuated. This may result in a low lying region within the bag that is proximate to the spout attached to the bag and that which is at the bottom of the tray. This low lying region acts as a reservoir of fluid that remains unevacuated and thus wasted, even with a helical channel disclosed in the Bond patent. This problem is clearly exacerbated when thicker fluids, more viscous fluids, are to be evacuated due to their natural tendency to resist flowability.
Accordingly, a need has continued to exist for a mounting that can address the evacuation problem, and especially the evacuation problem when viscous fluids are used.